It is generally desirable in minimally invasive medical procedures involving instruments such as catheters, probes, and the like to understand the spatial positioning of such instruments relative to nearby tissue structures, such as the walls of a cavity of a heart. In the cardiovascular market, for example, several systems are available for tracking position, or “localizing”, instruments—including but not limited to the system sold under the tradename “EnSite™” by St. Jude Medical, Inc., and the system sold under the tradename “CartoXP™” by the Biosense Webster division of Johnson & Johnson, Inc. The EnSite system utilizes potential differences between reference patches and instruments to localize instruments while the CartoXP system utilizes magnetic fields and currents detected by small coils coupled to an instrument to localize such instrument. Fiber bragg (hereinafter “FBG”) sensor technology and configurations have been disclosed, for example in U.S. Patent Applications 60/785,001, 60/788,176, 60/899,048, 60/900,584, 11/690,116, 60/925,449, 60/925,472, 60/964,773, 61/003,008, 12/012,795, 12/106,254, the entirety of which are incorporated herein by reference, which allow for localization and shape sensing of elongate instruments. Depending upon the particular FBG configuration, such technology may enable not only localization of particular points along an elongate instruments, as with the aforementioned localization technologies, but also localization of the spatial position of an entire section of the length of such instrument—or the entire length of the instrument, for that matter. It would be advantageous to combine certain aspects of FBG localization and shape sensing technologies with more conventional localization technologies, such as those available from Biosense or St. Jude Medical, to provide a hybrid localization system capable of addressing certain shortcomings of the systems as individually deployed. Several such configurations are described here.